Refining and stabilization of vitamin-containing materials



was Apr. 4, i944 REFINING AND STABILIZATION OF VITA-= MIN-CONTAINING MATERALS Loren 0. Bnxton, Belleville, N. J., assignor'to National Oil Products Company, n, N. J., a corporation or New Jersey No Drawing. Application July 25, 19411, Serial No. @3996 on. on-er) 13 Claims.

This invention relates to the refining and stabilization of vitamin-containing materials, more particularly to the refining of fat-soluble vitamin-containing oils and concentrates and the Zitabilization thereof against oxidative deterioraon. I

Asia wellknown in the art, fat-solublevitamin-containing oils-and concentrates prepared therefrom have been used for a wide variety oi useful purposes, particularly in the nutritional fields. However, many or these fat-soluble vitamin-containing materials, particularly products of fish origin, have characteristic tastes and odors or an unpleasant nature; furthermore, the color of these materials is often dark, thus rendering the materials unattractive from a consumer standpoint. These undesirable properties have in some cases tended to limit the field of usefulness of these materials; as a resultthere has been a great demand for a simple and effective process for removing the objectionable color, odor and taste therefrom.

Ethos been proposed to improve the flavor and odor of the unsaponiflable fraction of fish liver oils through the removal of certain constituents responsible therefor by dissolving the unsaponifiable matter in a suitable solvent and percolating the same through a column or the like containing an n or vegetable carbon or earth. The unsaponifiable matter contains the vitamin A of the fish oil, and since vitamin A is eflicient process forreflning fat-soluble vitaminbearing materials, I have developed the process activated carbon, under anaerobic .conditions.

Because of the excellent solubility of fat-soluble vitamin-containinginaterials in hydrocarbon and halogenated hydrocarbon solvents of a relahighly sensitive to oxygen and likely to be destroyed thereby in this process which has been it has been passed through the carbon in the column with an alkaline solution, which removes the antioxidant. Not only is the process cumbersome and costly, but also it has been found that such antioxidants do notfunction any too well in their role of protecting the vitamins from destruction by oxidation: and, of course, since the antioxidants must be removed after the refining treatment, they can in no way give the vitamins any protection from oxidation during the time ensuing between the refining and the ultimate consumption of the vitamin-containing material by the consumer. process has displayed a slight degree of merit on a laboratory scale, it is not, in view of the disadvantages herein set out, very satisfactory for commercial practice.

In order to meet the demand for a simple,

Although such a.

proposed, the system is kept flooded with carbon I tively non-polar nature, these substances are recommended among others for use as solvents for the fat-soluble vitamin-containing materials in this process. subsequent investigations, however, revealed that when solutions of fat-soluble vitamin-containing materials in hydrocarbon or halogenated hydrocarbon solvents were contacted with certain types of very highly active adsorbents, such as activated earths and clays or blood charcoal, some or the valuable vitamins were adsorbed along with the undesirable constituents and thereby lost.

To overcome that disadvantage, the process which is disclosed and claimed in copending application Serial No. 374,080, filed January 11, 1941, in the names of Buxton and Simons, was developed, which issuedDec. 16, 1941, as Pat. No. 2,266,719. It was found that by incorporating a relatively small amount (not more than 10%) of an oxygen-containing organic compound having a polar functional grouping into the hydrocarbon or halogenated hydrocarbon solvent, the undesirable constituents contained in fat-soluble vitamin-containing materials which are responsible for objectionable odor, color and taste may be removed therefrom without the loss of substantially any of the valuable vitamins by con; tacting such a solvent solution of vitamin-containing materials with a highly active adsorbent. The term "polar functional grouping is used to connote the functional grouping in a compound which tends to produce an unbalanced electronic structure, and thereby activates the molecule and imparts a characteristic dipole moment thereto; examples of such polar functional groupings are the hydroxyl group, the carbonyl group, the carboxyl group, and the ester group.

By using the process of either oi. the aboveidentified inventions, it is possible to produce highly refined vitamin-containing materials havthese vitamin-containing materials by being adsorbed on the absorbent. Cons-esrently. after being refined, these vitamin products are less stable towards oxidative changes than are the unrefined materials; and frequently undesirable oxidative changes take place therein during the time between the refining and the ultimate consumption of the products.

In carrying out experiments relating to the solvent extraction of fatty materials, I have found that by treating natural antioxidant-containing' fatty vegetable materials with certain types of organic solvents, highly potent extracts containing themajority of the natural antioxidants of the fatty vegetable material concentrated therein may be obtained. Thus I have found that a highly potent antioxidant extract may be obtained from a natural antioxidant-containing vegetable oil by contacting said oil with a suitable solvent at room temperature or above, such that at least the major portion of the oil is miscible with the solvent, and then cooling the mixture to the table below:

TABLE 1. Aliphatic and'alicyclic monohydroxy alcohols containing from 3 to 6 carbon atoms. 2. Esters formed by the reaction of aliphatic and Other objects of the invention will in part be obvious and will in part appear hereinafter.

I have found that the above and other objects of the invention may be accomplished by refining vitamin-containing materials in accordance with the process of application Serial No. 227,599, or the process of application Serial No. 374,080 by incorporating into the vitamin-containing map terial before it is refined, natural oil-soluble antioxidants obtained from vegetable materials in accordance with either the process of application Serial No. 351,909 or application Serial No. 897.-

547, or antioxidants similar to the ones produced by those processes, but produced by other proc-- cases. For example, antioxidants concentrated fromvegetable oils by highvacuum distillation may be used. Vitamin E and its homologues may be also employed in practicing this invention. These natural antioxidants are not removed in any substantial amount from the vitamin-containing materials by the refining process, and therefore the refined materials which are obtained are much more stable towards future oxidative changes than materials similarly refined, but to which no natural antioxidants have been added. In fact, in some cases the refined prodnets are more stable toward deteriorative oxidative changes than are the crude materials. A

, further advantage of this process is that it also alicyclic alcohols with aliphatic monocarboxylic acids, 'said esters containing not more than 8 carbon atoms.

3. Aliphatic and alicyclic aldehydes containing not more than 6 carbon atoms. 4. Aliphatic ketones containing not more than 6 carbon atoms.

It will be noted that these preferred solvents are all liquid organic compounds having the properties of being substantially miscible with fatty oils at temperatures above room temperature and partially immiscible therewith at temperatures substantially below room temperature; experiments in this connection have shown that 301- vents of this class may be used generally in the processrhereinabove described. This process is more fully described and claimed in my copending applicationSerial'No. 351,909, filed August 8, 1940. I have also found that highly potent antioxidant'extracts may be obtained from natural antioxidant-containing vegetable materials that are'oil-bearing solids, e. g. oil-bearing wheat germ meal, corn germ meal, soybean meal, etc.,

by treatingthese materials with solvents by a process similar to that of ap n serial u.

351,909. This last mentioned process is more fully described and claimed in copending' appliodor from fat-soluble vitamin-containing materials without impairing the future stability to- .wards deteriorative oxidative changes of said materials. 7 I

removes certain undesirable colors associated with some of the natural vegetable antioxidants. Thus a highly stable, light-colored product substantially devoid of undesirable tastes and odors is obtained. As these antioxidants are entirely nontoxic, any amount of them may be added as is desired. However, in most cases only relatively small amounts of them will be required,

The preferred embodiment of my invention involves contacting a solvent solution of a fish liver oil or concentrate prepared therefrom, and to which has been added a natural oil soluble vegetable antioxidant concentrate, under. anaerobic conditions with an adsorbent, such as activated carbon or charcoal or an activated earth or clay;

, by operating in this manner highly valuable products may be inexpensively produced from the readily available fish liver oils.

The fat-soluble yitamin-containing materials which may be treated in accordance with my invention may be any material containing substantial quantities of the fat-soluble vitamins from which it may be desired to remove undesirable color, taste or odor; thus, for example, fish liver oils, such as cod liver oil, shark liver oil, ling cod liver .oil, halibut liver oil, tuna liver oil, mackerel form, or provitamin A or electrically or chemically activated formsofvitamin D may also be advantageously refined by the process of this invention.

The adsorbents employed may be practically any adsorbent capable of removing constituents responsible for the objectionable color, taste or odor of a fat-soluble vitamin-containing material. Thus, for example, the various types of decoloriz-. ing carbons, e. g. blood charcoal or activated animal orvegetable carbons, may be employed;v

Furthermore, earths or clays activated by treatment with acid or heat such as fullers earth, *Tonsilj: and similar products may be used in conjunction with the activated carbon. Any one of the many aluminum oxide adsorbents known to thet'artma'y also be employed along with the carbon'adsorbent.

.The fat-soluble vitamin-containing material may, in accordance with this invention, be contacted with the adsorbents in a variety of ways. Preferably the process is carried out under anaerobic conditions according to the procedure described in copending application Serial No. 227,599, of Buxton, filed August 30, 1938. In accordance with this procedure one of the adsorbents above mentioned is first thoroughly deaerated by agitating the same with the solvent to be used as the solvent for the fat-soluble vitamin-containing material. Solvents which maybe used include, inter alia, hexane, heptane, octane, ethylene dichloride, carbon tetrachloride, cyclohexane, methyl cyclohexane, benzene, trichloroethylene and generally the hydrocarbon and halogenated hydrocarbon solvents and mixtures thereof. Polar solvents used in conjunction with the nonpolar solvents include, among others, methyl alco hol, ethyl alcohol, propyl alcohol, isopropyl alcohol, cyclohexanol, acetone, methylethyl ketone, methyl acetate, methyl formate, ethyl acetate,

. and mixtures of such solvents or similar solvents.

In the carbon refining of the unsaponifiable frac tion of fish liver oils, any one of the foregoing polar solvents may be used alone to the exclusion of the non-polar solvents, if desired. The deaeration is preferably accomplished by mixin the solvent vapor zone created directly over the mass to prevent access of air. Heat and reduced pressures may be applied to assist or accelerate the deaeration, if desired. Furthermore, it is not necessary to add all thesolvent to the adsorbent prior to deaeration, since a portion can be used to deaerate the adsorbent and the remainder subse-, quently added to the mass either alone or along with the vitamin material to be refined. In any stability towards oxidative changes and in many cases markedly improving such stability with respect to the crude material.

When the adsorbent has been deaerated, the fat-soluble vitamin-containing material to which the natural vegetable antioxidants have been added may then be added to the deaerated mixture; the amount of material added should be such that the weight of fat-soluble vitamin-containing material is not greater than the weightof the solvent, and preferably it should be between about 15% and about 20% of the weight of the solvent. Tht fat-soluble vitamin-containing material added may be dissolved in a solvent compatible with the solvent in which the adsorbent is deaerated; thus, for example, solutions containing fat-soluble vitamins such as those obtained by the solvent extraction of fish livers or fish liver oils may be treated. The mass may then be stirred for a suitable time, with the application of heat and reduced pressure, if desired, until adsorption of the undesirable constituents has been completed; it will be found that approximately one hour is usually suflicient to adsorb the bulk of the objectionable constituents from the fat-soluble vitamin-containing material. The suspended adsorbent may then be permitted to settle, the mass filtered and the residue washed with the particular solvent employed in order to remove any fat-soluble vitamins from the adsorbents. The wash liquids may then be combined with the filtrate, the solvent evaporated and the refined fat-soluble vitamin-containing material thus recovered.

It is to be understood that thefprocess of my invention may be modified somewhat. Thus, for example,the fat-soluble vitamin-containing material containing the natural vegetable antioxidants may be dissolved in a suitable solvent of the type above described and this solution then erably one which has been deaerated by contact event at the termination of the deaeration treat-.

ment, entrapped air will be entirely expelled from the adsorbent and vapors of the solvent will prevent air from contacting the adsorbent-vitamin though, if .desired, the antioxidant may be added to the mixture after the vitamin-containing material has been added thereto. The amount of antioxidant extract which is added may vary considerably, depending upon the activity of the extract and the degree of instability which the' vitamin-containing material wouldexhibit after being refined if no antioxidants were added thereto. I have found that fat-soluble vitamin.- containing oils and concentrates to which from 0.1% to about 20%, preferably from 0,.5% to 5%, ofmy antioxidant extracts have been added,

may be refined by means of adsorbents as herein set out without materially affecting their future with a solvent of a type similar to that used for thematerial being refined; this method of op-.

eration has the advantage of being substantially continuous. If the fat-soluble vitamin-conta ning material to be refined contains free fatty acids, a portion of these may be removed prior to refining in accordance with the process described in copending application Serial No. 227,600, filed August 30, 1938 in the names of Buxton and Simons, which issued Sept. 16, 1941, as Patent No. 2,255,875. The adsorbents used may contain filter aids to assist in their removal from the refined material. Other modifications may also be introduced without departing from the scope of this invention.

For a fuller understanding of the nature and objects .of the invention, reference should be had to the following examples which are given.

merely to further illustrate the invention and are not to be construed in a limiting sense, all parts given being by weight.

EXAMPLE I parts of crude shark liver oil containing 103,000 U. S. P. units of vitamin A/gm. were mixed with5 parts of an antioxidant fraction extracted from wheat germ oil by the process in patent application Serial No. 351,909. Th s mixture was then added to 400 parts of heptane containing suspended therein 20 parts of an activated carbon (Nuchar XXX). This mixture was stirred for 30 minutes at room temperature.

The activated carbon was removed by filtration and the solvent removed under reduced pressure. The resulting oil was devoid of fishiness, light yellow in color, and more stable than the crude oil. The vitamin A content of the refined oil was substantially the same as that pf the unrefined material.

EXAMPLE II EXAMPLE III 190 parts of halibut liver oil containing 78,000 U. S. P. units of vitamin A/gm. and'5,000 U. S. P. units of vitamin D/gm. were mixed with parts of an antioxidant concentrate extracted from freshly prepared com germ meal by the process in patent application Serial No. 397,547. This mixture was then added to 600 parts of 97% cyclohexane (3% of isopropanol) containing suspended therein 10 parts of an activated carbon (Darco G-60). This mixture was agitated for 1 hour at room temperature. The activated carbon was then removed by filtration and the solvent evaporated under reduced pressure. The resulting oil was substantially odorless, tasteless, light yellow in color, and more resistant to oxidation than the crude oil. The vitamin A and D content of the refined and stabilized product was unchanged.

The stability of the refined oils and that of the same crude fish liver oils similarly refined, except that io vegetable antioxidant was added to the oil, was determined by carrying out stability tests under accelerated conditions. In these tests the oils were maintained at a constant temperature of 34.5" C. in the presence of air for a number of days and the percentage of vitamin A destroyed then determined. The results of these tests are given in Table A.

antioxidant obtained from crude vegetable oils or meals by any suitable process including those described in aforesaid applications Serial Nos. 351,- 909 and 397,547.

Since certain changes may be made in carrying out the above process without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A process of removing objectionable color, odor and taste from fat-soluble vitamin-containing materials, which comprises admixing activated carbon with an organic solvent, deaerating the carbon-solvent mixture by means of agitation, adding to the deaerated carbon-solvent mixture the fat-soluble vitamin-containing material and a small amount of a natural antioxidant concentrate prepared by contacting a natural antioxidant-containing material selected from the group consisting of vegetable oils and vegetable oil-bearing solids, at a temperature above room temperature with a solvent selected from the group consisting of aliphatic and alicyclic monohydroxy alcohols containing 3 to 6 carbon atoms, esters formed by the reaction of aliphatic and alicyclic alcohols with aliphatic monocarboxylic acids, said esters containing not more than 8 carbon atoms, aliphatic and alicyclic aldehydes containing not more than 6 carbon atoms and aliphatic ketones containing not more than 6 carbon atoms, cooling the mass to a temperature within the range of 0 C. to 70 0. whereby layers are formed, separating the solvent layer from the insoluble residues and removing the extracted natural antioxidant concentrate from the solvent, agitating the entire mass to effect adsorption of impurities on the carbon and separating the refined antioxidant containing fat-soluble vitamin-containing material and solvent from the carbon and impurities adsorbed thereon.

2. A process of removing objectionable color, odor and taste from fat-soluble vitamin-containing materials, which comprises admixing activated carbon with an organic solvent, deaerating the carbonsolvent mixture by means of agitation, adding to the deaerated carbon-solvent mixture the fat-soluble vitamin-containing material containing a small amount of a natural antioxidant concentrate prepared by contacting a Table A Per cent vitamin A destroyed in Sample 4 days 6 days 14 days Shark liver oil refined without adding antioxidants 38. 2 70. 8 Shark liver oil refined in the presence of 5% of an antioxidant concentrate prepared from wheat germ oil 7. 5 26. 3 Shark liver oil refined .in the prsence of 5% of an antioxidant concentrate prepared irom a 50-50 mixture of wheat germ oil and soybean oil i2. 3 35. I; Halibut liver oil refined without adding antioxidants 19.1 50. 4 Halibut liver oil refined in the presence of 5% of an antioxidant concentrate I prepared .from corn germ meal 4. 6 12.0 28. 0

natural antioxidant-containing material selected from the group consisting of vegetable oils and vegetable oil-bearing solids, at a temperature above room temperature with a solvent selected from the group consisting of aliphatic and allcyclic monohydroxy alcohols containing 3 to 6 carbon atoms, esters formed by the reaction of aliphatic and alicyclic alcohols with aliphatic monocarboxylic acids, said esters containing not 1 more than 8 carbon atoms, aliphatic and alicyclic aldehydes containing not more than 6 carbon atoms and aliphatic ketones containing not more than 6 carbon atoms, cooling the mass to'a temperature within the range of 0 C. to -'70 C. whereby layers are formed, separating the sqvent layer'from the insoluble residues and re'- moving the extractednatural antioxidant concentrate from the solvent, agitating the entire' masswhile heating the same to eifect adsorption of impurities-on the carbon, and separating the refined antioxidant containing fat-soluble vitamin-containing material and solvent from the carbon and impurities adsorbed thereon.

3. A process of removing objectionable color, odor and taste from fat-soluble vitamin-containing materials, which comprises admixing activated carbon and colloidal clay with an organic solvent, deaerating the clay-carbon-solvent mixture by means of agitation, adding to the deaerated clay-carbon-solvent mixture the fat-soluble vitamin-containing material containing a small amount of a natural antioxidant concentrate prepared by contacting a natural antioxidant-containing material selected from the group consisting of vegetable oils and vegetable oil-bearing solids, at a temperature above room temperature with a solvent selected from the group consisting of aliphatic and alicyclic monohydroxy alcohols containing 3 to 6 carbon atoms, esters formed by the reaction of aliphatic and alicyclic alcohols with aliphatic monocarboxylic acids, said esters containing not more than 8 carbon atoms, aliphatic and alicyblic aldehydes containing not more than 6 carbon atoms and aliphatic ketones containing not more than 6 carbon atoms, cooling the mass to a temperature within the range of 0 C. to 70 C. whereby layers are formed, separating the solvent layer from the insoluble residues and removing the extracted natural antioxidant concentrate from the solvent, agitating the entire mass to efiect adsorption of impurities on the carbon and clay, and separating the refined antioxidant containing fat-soluble vitamin-containing material and solvent from the clay, carbon and impurities adsorbed thereon. I

4. A process of removing objectionable color, odor and taste from fat-soluble vitamin-containing materials, which comprises admixing activated carbon with a hydrocarbon solvent, deaerating the carbon-solvent mixture by means of agitation, adding to the deaerated carbon-solvent mixture the fat-soluble vitamin-containing material containing a small amount of a natural antioxidant concentrate prepared by contacting a natural antioxidant-containing material selected from the group consisting of vegetable oilsand vegetable oil-bearing solids, at a temperature above room temperature with a solvent selected from the group consisting of aliphatic and alicyclic monohydroxy alcohols containing 3 to 6 carbon atoms, esters formed by the reaction of aliphatic and alicyclic alcohols with aliphatic monocarboxylic acids, said esters containing not more than 8 carbon atoms, aliphatic and alicyclic aldehydes containing not more than 6 carbon atoms and aliphatic ketones containing not more than 6 carbon atoms, cooling the mass to a temperature within the range of 0 C. to -70 C. whereby layers'are formed, separating the solvent layer from the insoluble residues and removing the extracted natural antioxidant concentrate from the solvent, agitating the entire mass to effect adsorption oi impurities on the carbon, and separating the refined antioxidant containing fat-soluble vitamin-containing material and solvent from the carbon and impurities adsorbed thereon.

5. A process of removing objectionable color, odor and taste from fat-soluble vitamin-containterial selected from the group consisting of vegetable oils and vegetable oil-bearing solids, at a temperature above room temperature with a solvent selected from the group consisting of, aliphatic and, alicyclic monohydroxy alcohols containing 3 to 6 carbon atoms, esters formed by the reaction of aliphatic and alicyclic alcohols with aliphatic monocarboxylic acids, said esters containing not more than 8 carbon atoms, aliphatic and alicyclic aldehydes containing not more than 6 carbon atoms and aliphatic ketones containing not more than 6 carbon atoms, cooling the mass to a temper;ature within the range of 0 C. to '70 'C. whereby layers are formed, separating the solvent layer from the insoluble residues and removing the extracted natural antioxidant concentrate from the solvent, agitating the entire mass to. effect adsorption of impurities on the carbon, and separating the refined antioxidant containing fat-soluble vitamin-containing material and solvent from the carbon and impurities adsorbed thereon.

6. A process of removing objectionable color, odor and taste from fish liver oils, which comprises admixing activated carbon with a hydrocarbon solvent, deaerating the carbon-solvent mixture by means of agitation, adding to the de= aerated carbon-solvent mixture a fish liver oil containing a small amount of a natural antioxidant concentrate prepared by contacting a natural antioxidant-containing material selected from the group consisting of vegetable oils and vegetable oil-bearing solids, at a temperature above room temperature with a solvent selected fromthe group consisting of aliphatic and alicyclic monohydroxy alcohols containing 3 to 6 carbon atoms, esters formed by the reaction of aliphatic and alicyclic alcohols with aliphatic monocarboxylic acids, said esters containing not more than 8 carbon atoms, aliphatic and alicyclic aldehydes containing not more than 6 carbon atoms and aliphatic ketones containing not more than 6 carbon atoms, cooling the mass to a temperature within the range of 0 C. to 70 C. whereby layers are formed, separating the solvent layer from the insoluble residues and removing the extracted natural antioxidant concentrate ing materials, which comprises admixing activated carbon with a chlorinated hydrocarbon solvent, deaerating the carbon-solvent mixture by means of agitation, adding to the deaerated carbon-solvent mixture the fat-soluble vitamincontaining material containing a small amount of a natural antioxidant concentrate prepared by contacting a natural antioxidant-containing mafrom the solvent, agitating the entire mass to effect adsorption of impurities on the carbon, and separating the refined antioxidant containing fish liver oil and solvent from the carbon and impurities adsorbed thereon.

7. A process of removing objectionable color, odor and taste from fish liver oils, which comprises admixing activated carbon with a chlorinated hydrocarbon solvent, deaerating the carbon-solvent mixture by means of agitation, adding to the deaerated carbon-solvent mixture a fish liver oil containing a small amount of a natural antioxidant'concentrate prepared by contacting a natural antioxidant-containing material selected from the group consisting of vegetable oils and vegetable oil-bearing solids, at a temperature above room temperature with a solvent selected from the group consisting of aliphatic and alicyclic monohydroxy alcohols containing 3 to 6 carbon atoms, esters formed by the reaction of aliphatic and alicyclic alcohols with aliphatic monocarboxylic acids, said esters containing not more than 8 carbon atoms, aliphatic and-alicyclic aldehydes containing not more than 6 carbon atoms and aliphatic ketones containing not more than 6 carbon atoms, cooling the mass to a temperature within the range of 0 C. to -'70 C. whereby layers are formed,

separating the solvent layer from the insoluble residues and removing the extracted natural antioxidant concentrate from the solvent, agitating the entire mass" to eflect adsorption of impurities on the carbon, and separating the refined antioxidant containing fish liver oil and solvent from the carbon and impurities adsorbed thereon.

8. The process set forth in claim 4, wherein a relatively small quantity of a polar solvent is in cluded in the hydrocarbon solvent.

9. The process set forth in claim 5, wherein a relatively small quantity of a polar solvent is included in the chlorinated hydrocarbon solvent.

10. The process set forth in claim 6, wherein a relatively small quantity of a polar solvent is included in the hydrocarbon solvent.

11. The process set forth in claim 7, wherein a relatively small quantity of-a polar solvent is included in the chlorinated hydrocarbon solvent.

12. The process set forth in claim 6, wherein a relatively small quantity or a lower aliphatic alcohol is included in the hydrocarbon solvent.

13. The process set forth in claim 7, wherein a relatively small quantity of a lower aliphatic alcohol is included in the chlorinated hydrocarbon solvent.

LORAN O. BUXTON. 

